[PATCH v2] serial: 8250_of: Add basic PM runtime support

[Franklin S Cooper Jr]

Add basic PM Runtime support.

Signed-off-by: Franklin S Cooper Jr <fcoo...@ti.com>
---

Version 2 changes:
Fix build error.
Build tested using allmodconfig

 drivers/tty/serial/8250/8250_of.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_of.c 
b/drivers/tty/serial/8250/8250_of.c
index 6c5a8ca..9bad8bae 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -18,6 +18,7 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/pm_runtime.h>
 #include <linux/clk.h>
 #include <linux/reset.h>
 
@@ -65,6 +66,10 @@ static int of_platform_serial_setup(struct platform_device 
*ofdev,
        int ret;
 
        memset(port, 0, sizeof *port);
+
+       pm_runtime_enable(&ofdev->dev);
+       pm_runtime_get_sync(&ofdev->dev);
+
        if (of_property_read_u32(np, "clock-frequency", &clk)) {
 
                /* Get clk rate through clk driver if present */
@@ -72,12 +77,13 @@ static int of_platform_serial_setup(struct platform_device 
*ofdev,
                if (IS_ERR(info->clk)) {
                        dev_warn(&ofdev->dev,
                                "clk or clock-frequency not defined\n");
-                       return PTR_ERR(info->clk);
+                       ret = PTR_ERR(info->clk);
+                       goto err_pmruntime;
                }
 
                ret = clk_prepare_enable(info->clk);
                if (ret < 0)
-                       return ret;
+                       goto err_pmruntime;
 
                clk = clk_get_rate(info->clk);
        }
@@ -170,8 +176,10 @@ static int of_platform_serial_setup(struct platform_device 
*ofdev,
 err_dispose:
        irq_dispose_mapping(port->irq);
 err_unprepare:
-       if (info->clk)
-               clk_disable_unprepare(info->clk);
+       clk_disable_unprepare(info->clk);
+err_pmruntime:
+       pm_runtime_put_sync(&ofdev->dev);
+       pm_runtime_disable(&ofdev->dev);
        return ret;
 }
 
@@ -227,8 +235,9 @@ static int of_platform_serial_probe(struct platform_device 
*ofdev)
        return 0;
 err_dispose:
        irq_dispose_mapping(port8250.port.irq);
-       if (info->clk)
-               clk_disable_unprepare(info->clk);
+       pm_runtime_put_sync(&ofdev->dev);
+       pm_runtime_disable(&ofdev->dev);
+       clk_disable_unprepare(info->clk);
 err_free:
        kfree(info);
        return ret;
@@ -244,8 +253,9 @@ static int of_platform_serial_remove(struct platform_device 
*ofdev)
        serial8250_unregister_port(info->line);
 
        reset_control_assert(info->rst);
-       if (info->clk)
-               clk_disable_unprepare(info->clk);
+       pm_runtime_put_sync(&ofdev->dev);
+       pm_runtime_disable(&ofdev->dev);
+       clk_disable_unprepare(info->clk);
        kfree(info);
        return 0;
 }
@@ -259,9 +269,10 @@ static int of_serial_suspend(struct device *dev)
 
        serial8250_suspend_port(info->line);
 
-       if (info->clk && (!uart_console(port) || console_suspend_enabled))
+       if ((!uart_console(port) || console_suspend_enabled)) {
+               pm_runtime_put_sync(dev);
                clk_disable_unprepare(info->clk);
-
+       }
        return 0;
 }
 
@@ -271,8 +282,10 @@ static int of_serial_resume(struct device *dev)
        struct uart_8250_port *port8250 = serial8250_get_port(info->line);
        struct uart_port *port = &port8250->port;
 
-       if (info->clk && (!uart_console(port) || console_suspend_enabled))
+       if ((!uart_console(port) || console_suspend_enabled)) {
+               pm_runtime_get_sync(dev);
                clk_prepare_enable(info->clk);
+       }
 
        serial8250_resume_port(info->line);
 
-- 
2.9.4.dirty